This invention relates generally to improvements in rotors comprised of porous material to quietly pass fluid, such as gas, as such rotors rotate; and more particularly to such rotors operating as blowers or turbines by virtue of connection to driving or driven rotary structures.
U.S. Pat. No. 4,795,314 describes a quiet hair drier device wherein air is caused to pass through an annulus of porous material, such as foam, acting as a pump as the foam rotates. There is need to increase the air moving efficiency of such devices; and there is need to provide a class of efficiently operating devices wherein gas is caused to pass through rotating foam, or cellular structure, in a quiet manner, as in blowers or turbines.